The present invention generally relates to heating and air conditioning equipment and, in a preferred embodiment thereof, more particularly relates to roof curbs used to underlie and operatively support heating and air conditioning units on a roof.
Frame-shaped structures commonly referred to as roof curbs are typically used to support heating and air conditioning units on roofs to supply heated or cooled air to conditioned spaces below the roof. The typical roof curb has a rectangular frame body portion which is comprised of four side wall portions which are secured together at the job site, the assembled body portion extending above the roof and forming a base structure upon which a heating and air conditioning may be operatively placed.
As conventionally assembled, the four side wall portions of the curb are bolted or screwed together at the corners of the curb, with all of the fasteners being manually put into place at the job site. As is well known in the industry, this traditional method of constructing a roof curb is a time-consuming and relatively expensive task.
A previously proposed solution to these problems associated with the use of threaded fasteners to intersecure the side wall portions at the corners of a roof curb is illustrated and described in U.S. Pat. No. 5,148,647 to Rutledge in which a hinge-like structure is integrally formed on the ends of the roof curb side wall portions and configured to be joined together with pin structures driven into the hinge structures at the four corners of the roof curb. While this hinge/pin corner joining structure tends to speed up the overall roof curb assembly process, the pins used in securing the corners, as well as the formation of the hinge joints at the side wall ends, tend to be undesirably expensive. Moreover, the hinge portions on the contiguous curb side wall portion ends must be precisely aligned by hand to properly receive the pin driven into the hinge portions.
In view of these problems, limitations and disadvantages typically associated with conventional techniques for assembling roof curbs it can readily be seen that a need exists for further improvements in such assembly techniques. It is to this need that the present invention is directed.